1. Field of the Invention
The present invention relates to a display apparatus employing a liquid crystal panel, and to a light source device capable of maintaining high display quality and a display apparatus including the light source device.
2. Description of Related Art
In the recent display apparatuses employing a liquid crystal panel, edge light type light source devices are commonly used for thinning the display apparatus. The edge light type light source device is configured such that light emitting diodes are disposed to face one or more side faces of a light guide plate whose one broad surface faces the liquid crystal panel at a prescribed interval. Thereby light emitted from the light emitting diodes progresses from the side surface into the light guide plate, and the liquid crystal panel is uniformly irradiated with the light from the one broad surface of the light guide plate.
The light emitting diodes employed in the edge light type light source device have a structure called a surface mounted type, and are configured by disposing light emitting diode elements and a wiring group such as electrodes on a bottom surface of a deep-dish shaped housing body on which a reflection member is arranged on an inner surface, and filling jelly-like fluorescent bodies in the housing body. The light emitting diode elements and the wiring group are connected to each other by loosened wires, and are adapted so as not to affect emittance even if a positional shift occurs between the respective members due to a difference in heat expansion rates of the respective members such as the housing body, the light emitting diode elements, and the electrodes.
Since the light from the light emitting diodes is radially emitted from surfaces of the fluorescent bodies, there appears a luminous flux which is deviated toward the both broad surfaces while not entering into the side face of the light guide plate (hereinafter referred to as a light-entering surface). As a distance between the surfaces of the fluorescent bodies and the light-entering surface of the light guide plate is increased, loss of light is increased. Therefore, in terms of an incident efficiency to the light guide plate, it is preferable to have a configuration in which the surfaces of the fluorescent bodies and the light-entering surface of the light guide plate are as close to each other as possible. However, when vibrations or impacts are applied to the light source device itself, or when the light guide plate is thermally expanded due to heat of the light emitting diode elements, the light guide plate may contact the housing body. If a force from the light guide plate is applied to the housing body, the housing body itself is distorted. Since the jelly-like fluorescent bodies filled in the housing body become a state liable to be easily loosened by heat generated from the light emitting diode elements, if the housing body itself is distorted, the fluorescent bodies move within the housing body to apply a force to a portion at which the wire may be loosened, and a possibility of causing operation failure of the light emitting diodes such as a disconnection of the wire is increased.
In a conventional light source device of edge light type, in order to prevent a contact between the light guide plate and the light emitting diodes as described above, a configuration, in which a spacer is disposed between the light guide plate and the substrate on which the light emitting diodes are mounted, is employed. In particular, it is suggested that a configuration in which the spacer is provided so as to enclose light emitting diodes, thereby further reliably preventing the contact of the light guide plate with the light emitting diodes.